Alex Chia-Chun Hsu

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- As Machine-Type-Communications (MTC) continues to burgeon rapidly, a comprehensive study on overload control approach to manage the data and signaling traffic from massive MTC devices is required. In this work, we study the problem of RACH overload, survey several types of RAN-level contention resolution methods, and introduce the current development of(More)
— The MAC protocol of a cognitive radio (CR) device is supposed to enable the device to dynamically access unused or under-utilized spectrum without (or with minimal) interference to primary users. To fulfill such a goal, we propose a cognitive MAC protocol using statistical channel allocation and call it SCA-MAC in this work. SCA-MAC is a CSMA/CA-based(More)
— In this paper, we present an enhanced adaptive frequency hopping (EAFH) mechanism for improving the performance of frequency hopping-based wireless personal area networks (WPANs) under frequency-static and frequency-dynamic interference. The proposed mechanism monitors the overall packet error rate (PER) of the system to determine the right number of(More)
—Featuring massive number of devices, Machine Type Communications (MTC) poses great challenges for radio access network (RAN) with its overloading problem that has been aggressively addressed by 3GPP as an essential working item. In this article, we rst introduce random access procedure in LTE-A. Then we address the issue of RACH overload coming from(More)
—A non-collaborative coexistence mechanism for wireless-fidelity (Wi-Fi) and bluetooth (BT) systems based on dynamic packet fragmentation is proposed in this work. The basic idea is to adapt the packet length of Wi-Fi in the MAC layer such that the fragmented packet has a better chance to survive the interference from the nearby BT devices. We first develop(More)
—Dynamic spectrum access (DSA) technique enables dynamic access of unused or under-utilized spectrum without causing interference to existing incumbent service. Through DSA, a DSA device (second user) is offered opportunities to monitor a swath of spectrum, which is divided into myriad channels, in the licensed band. A great number of available channels(More)
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